1926 Model TT Restoration: Engine/Trans Rebuild

[Arisaka]

Those gears and the complexity are amazing considering how old the truck is. Great pics and explanation of the whole project my friend, how many Golden's can ride in it?

The cab is pretty tight. I figure I can take one big golden and one puppy. So, a 1.5 golden capacity

No room in the back with the tow rig?

Nope. That space is for you. The Goldens ride up front. Lol

[NWGunner]

[usrifle]

Those gears and the complexity are amazing considering how old the truck is. Great pics and explanation of the whole project my friend, how many Golden's can ride in it?

The cab is pretty tight. I figure I can take one big golden and one puppy. So, a 1.5 golden capacity

No room in the back with the tow rig?

Nope. That space is for you. The Goldens ride up front. Lol

[shaggy]

https://portland.craigslist.org/mlt/cto ... 20919.html

If anyone is enthused by this thread and looking for a REALLY rare heavier duty project like this, this seems pretty cool. There are very few of this make left (probably less than dozens)and this ran 10 years ago according to the add.

The downside is parts are unubtainium, so you'll need to make your own

[Arisaka]

My buddy has been working on my driveshaft assembly. It requires machining work, and he has access to a lathe and end mill.

Here is a standard Model TT driveshaft. The driveshaft is the skinny one. The driveshaft rotates inside the non-rotating torque tube. The fatter tube is the torque tube.




The forward end of the drive shaft is squared off and fits into a universal joint, which in turn connects to the transmission. Here is a look at those parts






Since I have a 12” long Warford auxiliary transmission installed behind the Ford transmission, the driveshaft and torque tube have to be shortened 12 inches. First up is the torque tube. Here is a full length torque tube




Here is a torque tube shortened 12 inches, by cutting off the end nearest to the differential. Those longer parts are radius rods that triangulate and stabilize the rear axle. They need to be shortened too.




The shortened torque tube then slides into a collar at the differential. Here it is test-fit in place.




Finally, a bushing is pressed into the forward end of the torque tube. The driveshaft rotates inside this bushing. You have to drill a hole in the side of the bushing, where it lines up with an external grease cup. That way the driveshaft receives grease at the bushing.




Next is the drive shaft. The drive shaft is cut off on its forward end, nearest the transmission. Then the flats have to be re-machined in the cut end to square it off, so it goes into the universal joint.




The other end of the driveshaft is splined, as is the worm gear in the differential. They just butt up, and this coupler holds them together




Here is the driveshaft test-fit to the differential




Next up is shortening the radius rods and then rolling the rear axle under the truck

Last edited by Arisaka on Thu Sep 15, 2022 5:55 pm, edited 1 time in total.

[NWGunner]

Sweet!

[Arisaka]

Summer chores are winding down, so I took another swing at the Model TT. As a review, the engine and transmission are rebuilt and installed. The auxiliary transmission is in. And a rebuilt rear axle is mounted. It was pretty clear the old rear axle was badly worn, and the axles had excessive in/out motion, which kept pushing my brake calipers out. And judging by the rest of the truck, I expected the whole axle was pretty much shot. Today, I got to take the old axle apart and do an autopsy.

Here is the old axle with the case split to let the gear oil out.






You can see how thick the 600W gear oil is




Once the gear oil is mostly out, the two axle housing are scooted apart enough to free up the worm drive. Here is the end of the worm coming out, with the thrust bearing leading the way




Here is the entire worm gear extracted from the case. The worms are steel, and rarely wear out. This one looks like it can be used by somebody else




One thing I wanted to check was the rear axle ratio in the old axle. There were two ratios available: the low-geared Farm Gear which was a 7.25:1, and a high-speed Express Gear which was a 5.17:1. Once you pull the worm out you can tell what you have. This worm had 4 teeth, which makes it the farm gear. The ring gear that it meshes with will have 29 teeth (29 divided by 4 = 7.25). If it was the desirable express gear, the worm would have had 6 teeth and the ring 31 teeth (31 divided by 6 = 5.17). Having the farm gear in this old axle was actually good news for me, as I know I have done over 30 mph with it. The new rear axle in the truck now is an Express Gear, so I should be able to do 40-45 mph now, which will help me keep up with traffic.


Anyway back to the old axle. Here are the axle housings coming off




Here are the axle housings




Here is what the rear axle looks like with the axle housings removed




Next step is to remove the inner axle bearings. This bearing is completely shot. Slops around everywhere, Its scrap. The other side is ok.




Then, its time to disassemble the inner case. First up unbolting the 29-tooth ring gear. Here it is covered in gear oil. This is the gear that meshes with the worm.




Here is the ring gear wiped off a bit



This ring gear is badly worn. The teeth should have a flat on the top, not a knife edge. And the teeth should not be scooped out in the center - they should be straight across. This gear is scrap. It is unbolted from the inner case and tossed in the copper scrap heap.

Here are the inner case halves separated, and the axles pulled out




Here are the axles:




Lots of wear on the axle ends




Found a surprise on the inside of the inner case. The spider gear was a pre-1923 design with only two spider gears



My truck is a 1926, and should have a 4-spider gear like this




So, somebody swapped in an earlier rear axle. Pretty common. My new axle has the 4-spider gear as was correct for 1926.


In summary, what can be saved are the outer axle bearings, the worm, one inner bearing, the outer axle housings and the inner case and 2-spider gear.




The axle housings are supposed to have grease seals to keep the differential gear oil from migrating down the axles and out into the rear emergency brakes. One side had a shot seal, as shown below. The other side had no seal at all.




Putting in a new rear axle was a good call. The old one was on its last legs, same as the engine was. I will be much happier with the new axle, with its 4-spider gears and Express ring gear, not to mention good bearings, better axles and oil seals all around.

What's left to do is to get the rear wheels on, re-plumb the juice brakes, put on the radiator, wire up the engine, install the distributor, hook up the carb linkage and put in all the fluids.

[NWGunner]

Fascinating.

That’s gonna be a smooth ride by the time you’re done

[usrifle]

How many Golden Retrievers can fit in that thing? I have two to add, three if you have the room.

[Old Growth]

Almost looks like #1 grease in that housing!

[Arisaka]

How many Golden Retrievers can fit in that thing? I have two to add, three if you have the room.

Always room for golden retrievers!

[shaggy]

Here are the axle housings

It looks like you now have a matching set of jack stands for the truck now... A friend of mine has probably used pair of model t axle tubes as jack stands for 40+ years. I've also seen them turned into stool bases.

[cmica]

WOW you sure are busy

[MadPick]

Wow . . . always cool to see the inner workings on this thing!

And that oil. Wow. That shit is persistent.

[RocketScott]

Love to see the progress

Thanks for documenting it so well too. Fascinating